@mixin reset-style {
  margin: 0;
  padding: 0;
}

@mixin light-style($selector,$attributes,$value) {
  @include reset-style;
  font-size: 14px;
  
  #{$selector} {
    #{$attributes}: $value;
  }
  
  .footer {
    position: fixed;
  }
}

.container {
  @include light-style('.header', color, skyblue);
}